Real-Time Physics Simulation Forum

First ask yourself why you are inventing your own orientation representation (Directional vector + Up vector) rather than using an existing representation. There are many to choose from. If you don't feel like learning quaternions, consider using a 3x3 matrix. Your representation is very much like a...

btQuat::angle actually measures the angle between the two 4d quaternions, not the angle you'd get if you converted the quat to an axis-angle format. An odd feature of quaternions is that every orientation is specified by two distinct quaternions: (x,y,z,w) and (-x,-y,-z,-w). These two quaternions ar...

A couple questions about allowedCcdPenetration. What is the intent of allowedCcdPenetration? Is it designed to improve gjk stability, or perhaps to allow the user to ignore grazing contacts? Or am I on the wrong track here? Also, what is the expected effect? I previously thought it was something lik...

If the architecture, abi, compiler, and math library all cooperate, then returning a vector by value is cheap -- it goes in a register. Also, the less aliasing means more opportunities for the compiler to optimize. It's not OK for the api to change between the scalar and simd implementations (the ch...

Is there a subtle reason btDispatcher::dispatchAllCollisionPairs() takes a btDispatcher* parameter? void btCollisionDispatcher::dispatchAllCollisionPairs( btOverlappingPairCache* pairCache, const btDispatcherInfo& dispatchInfo, btDispatcher* dispatcher) { btCollisionPairCallback collisionCallbac...

* Use btCompoundShape with optional dbvt. CON: ray and sweep tests don't use the acceleration structure ( issue 25 ). Also, seems like a slight abuse of shapes; nobody will care about the combined inertia tensor, for example. Issue 25 looks easy for me to implement, but it _has_ been sitting around...

I'm looking at issue 25 now. I notice that rayTestSingle mutates the passed collisionObject by calling internalSetTemporaryCollisionShape. Is this still necessary any more? It looks like the btCompoundShape recursive case already explicitly passes down all the information it needs through collisionS...

We divide our large world into chunks and wrap all static collision for a chunk into a Hk MOPP. The broadphase contains only a couple static objects -- one for the MOPP, one with a custom heightfield shape. There seem to be a few possiblilities to do this this in Bullet. * Forget the container; batc...

Thanks! I can successfully create spring-like behavior, but I am having trouble figuring out exactly what parameters will result in the pose being 100% matched, 50% matched, and so on, so that I can control it in a precise way. If you want the object to move N% of the way to the goal during a fixed...

Is there some way to get CMake to generate project files for use with the XDK and/or PS3 SDK? Or is everyone who needs them writing them by hand?